Does this mean support for microcontrollers from other series such as Texas Instruments MSP430 too?
Sure, in theory. In fact, the multiple uC architecture has been building for a while in multiple places, and you can already get ports for MSP430 (Engergia: GitHub - energia/Energia: Fork of Arduino for the Texas Instruments LaunchPad's ), ARM (Maple: Maple | LeafLabs and Teensy3: PJRC Store and probably others), PIC32 (ChipKit: http://www.digilentinc.com/Products/Catalog.cfm?NavPath=2,892&Cat=18 ) "Wiring" is also supposed to be multi-architecture.
These are all actually using forks of the Arduino IDE; not just libraries of similar core code...